1. Field of the Invention
This invention relates to an optical axis adjustable automobile lamp assembly, and more particularly to a lamp assembly for an automobile having a tilting member such as a lamp unit or reflector whose optical axis is adjustable by optical axis adjusting rods threadedly engaged with self-locking nuts relative to a support member such as a lamp unit or the like fixed to a vehicle body or a member thereon.
2. Description of the Prior Art
Automobile lamp assemblies such as automatic headlamps whose optical axes are adjustable relative to vehicle bodies are substantially classified into two types. One is the so-called reflector movable type whose optical axis is adjusted by moving a reflector as a tilting member relative to a lamp unit casing as a support member, while the other is the so-called lamp unit movable type whose optical axis is adjusted by moving a lamp unit as a tilting member comprising a reflector and a front lens relative to a support member such as a vehicle body or the like. In either type, there are commonly provided a plurality of optical axis adjusting rods and self-locking nuts threadedly engaged with the adjusting rods. Referring to FIG. 5 illustrating one example of the prior art reflector movable lamp, the same includes a lamp unit casing as a support member A fixed to a vehicle body or the like, a reflector as a tilting member B connected by a support leg rod 6 to the support member A, and self-locking nuts 2 secured to the tilting member B and threadedly engaged with optical axis adjusting rods 1 extending through the support member A from back side thereof. The optical axis adjusting rods 1 are threadedly operated so as to move the tilting member B relative to the support member A to adjust the optical axis of the lamp. On the other hand, with a lamp unit movable lamp as shown in FIG. 6, it includes a bracket as a support member fixed to a vehicle body or the like, and optical axis adjusting rods 1 extending through the bracket C and a support member R' of a lamp unit R as a tilting member and threadedly connected to self-locking nuts secured to the bracket C. The optical axis adjusting rods 1 are threadedly operated so as to move the lamp unit R as the tilting member relative to the bracket C as the support member on the side of the vehicle body to adjust the optical axis of the lamp.
With such conventional automobile lamp assemblies of these kinds, the self-locking nuts have been secured to the tilting or support members by caulking and press fitting to form unitary bodies unable to rotate relative to each other. In adjusting the optical axis, therefore, undue forces act on the mounting and supporting portions for the self-locking nuts, the threadedly engaged portions of the self-locking nuts with the optical axis adjusting rods, and the rotatably supporting portions for the optical axis adjusting rods (indicated by m and n in FIG. 5) because of somewhat rocking movement of the optical axis adjusting rods with the movements of the reflector or lamp unit in adjusting its optical axis. Accordingly, the optical axis adjusting operation cannot be smoothly effected and there is a risk of deformation or damage to the above portions subjected to the above undue forces and therefore to cause any deformation and play at these portions for a long period of use.
In order to solve these problems, an automobile headlamp assembly has been proposed. This headlamp assembly has self-locking nuts each formed with two engaging grooves extending in directions perpendicular to each optical axis adjusting nut so as to secure the self-locking nut to a tilting member or support member by means of the engaging grooves. Since, however, the two engaging grooves are made in the same configuration, the optical axis adjusting operation can be smoothly effected in the extending direction of the grooves (for example, for the horizontal optical axis adjustment), but cannot be sufficiently effected in the other directions (for example, for the vertical optical axis adjustment).